National Institute of Advanced Studies, Indian Institute of Science Campus, Bengaluru, Karnataka, 560012, India.
School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, 110067, India.
Environ Res. 2021 Nov;202:111780. doi: 10.1016/j.envres.2021.111780. Epub 2021 Jul 27.
The present study aims at the assessment of environmental quality of the most polluted stretch of river Yamuna along the megacity of Delhi. The study was conducted in order to examine toxicity and health hazards associated with persistent pollutants present in the fluvial ecosystem. Eighty four sediment and 56 vegetable samples from same locations were collected from the Delhi segment of river Yamuna flood plain in order to examine 20 organochlorine pesticides (OCPs) and 9 heavy metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn). Both the organic and inorganic groups of persistent toxic substances were monitored and analysed for the extent of eco-toxicological as well as dietary health risks posed to the local population. Eco-toxicological assessment was done based on sediment quality guidelines, enrichment factor, geo-accumulation index, degree of contamination and Pollution Load Index. The dietary-risk was assessed with the help of translocation factors (TF) of these pollutants in vegetables. Carcinogenic and non-carcinogenic health risks from consumption of vegetables were also investigated. The level of concern for heavy metals was greater than that of OCPs as per the sediment quality guidelines. DDT, Cd, Pb and Zn had maximum concentrations corresponding to level 3 of concern, while Cr and Ni reached up to the highest i.e., 4th level of concern. Sediment samples were found to be enriched and contaminated significantly with Cd and moderately with Pb, as represented respectively by enrichment factors and contamination factors (CF). CF for metals lied in order Zn > Cd > CrNi > PbCu. Pollution load index was highest at the location lying on the exit point of Yamuna in Delhi. TF values greater than 1 were observed in majority of samples analysed for Ni, Cr, Cu and Zn. Spinach topped among vegetables in terms of metal contamination. Cd, Ni and Pb accumulated more in the roots, as against Mn, Zn, Cu and Cr which had higher accumulation in the shoots. Translocation factors were substantially high in vegetables for most of the OCPs, clearly indicating bioaccumulation and potential health risk to the consumers. Health risk to humans was assessed for non-carcinogenic and carcinogenic potentials from ingestion of vegetables. Hazard Quotient (HQ) > 1 due to radish (roots and leaves) and cauliflower consumption in children indicated non-carcinogenic risk. Hazard Index (HI) beyond 1 for all the vegetables (except onion leaves) confirmed substantial cumulative risk. Lifetime cancer risk (LCR) revealed moderate (spinach, radish, beet root and cauliflower) to low (all the others) levels of carcinogenic risk to humans. Cancer risks from γ-HCH, β- HCH, Hept, Hept Ep, Ald, p,p'-DDT, and Cr exposure through the food chain could be well established.
本研究旨在评估德里市沿亚穆纳河污染最严重的河段的环境质量。该研究旨在检查河流水生态系统中存在的持久性污染物的毒性和健康危害。从亚穆纳河洪泛平原的德里段采集了 84 个沉积物和 56 个蔬菜样本，以检查 20 种有机氯农药 (OCPs) 和 9 种重金属 (Cd、Co、Cr、Cu、Fe、Mn、Ni、Pb 和 Zn)。对这两组持久性有毒物质进行了监测和分析，以评估其对当地居民造成的生态毒理学和饮食健康风险的程度。生态毒理学评估是基于沉积物质量指南、富集因子、地积累指数、污染程度和污染负荷指数进行的。利用这些污染物在蔬菜中的迁移因子 (TF) 来评估饮食风险。还研究了食用蔬菜的致癌和非致癌健康风险。根据沉积物质量指南，重金属的关注度高于 OCPs。DDT、Cd、Pb 和 Zn 的浓度最高，对应于关注级别 3，而 Cr 和 Ni 则达到了最高的第 4 级关注。沉积物样本被发现明显富集和严重污染 Cd 和适度污染 Pb，分别由富集因子和污染因子 (CF) 表示。金属的 CF 顺序为 Zn>Cd>CrNi>PbCu。污染负荷指数在位于德里亚穆纳河出口处的地点最高。分析的大多数样本中，Ni、Cr、Cu 和 Zn 的 TF 值大于 1。就金属污染而言，菠菜在蔬菜中位居榜首。与 Mn、Zn、Cu 和 Cr 相比，Cd、Ni 和 Pb 在根部积累更多，而 Mn、Zn、Cu 和 Cr 在茎部积累更多。大多数 OCPs 在蔬菜中的迁移因子都很高，这清楚地表明了生物积累和对消费者的潜在健康风险。通过食用蔬菜评估了非致癌和致癌潜力对人类的健康风险。由于儿童食用萝卜（根和叶）和菜花，危害系数 (HQ) > 1，表明存在非致癌风险。所有蔬菜（洋葱叶除外）的危害指数 (HI) 均超过 1，表明存在大量累积风险。终生癌症风险 (LCR) 表明人类面临中度（菠菜、萝卜、甜菜根和菜花）到低度（其他所有）的致癌风险。通过食物链从 γ-HCH、β-HCH、Hept、Hept Ep、Ald、p,p'-DDT 和 Cr 暴露致癌的风险可以得到很好的证实。
